MALARIA 1.2 (AB) Flashcards
(121 cards)
1
Q
What does the malaria parasite consume and degrade inside the RBC?
A
Hemoglobin
2
Q
What is the toxic byproduct of hemoglobin degradation by the malaria parasite?
A
Hemozoin (malarial pigment)
3
Q
How does the malaria parasite alter the RBC membrane?
A
By changing its transport properties
4
Q
What happens to the shape and deformability of infected RBCs?
A
They become more irregular
5
Q
Why do irregularly shaped RBCs cause hypoxia?
A
Because they can’t pass through capillaries easily
6
Q
What parasite causes knob formation on RBCs?
A
Plasmodium falciparum
7
Q
What is the role of PfEMP1?
A
Mediates cytoadherence of RBCs to vascular endothelium
8
Q
Which vascular receptor is associated with cerebral malaria?
A
ICAM-1 and endothelial protein C receptor
9
Q
Which vascular receptor is associated with placental malaria?
A
Chondroitin sulfate B
10
Q
Which vascular receptor is involved in most organs?
A
CD36
11
Q
What are the three mechanisms by which infected RBCs obstruct microcirculation?
A
Cytoadherence
12
Q
What is the result of sequestration of infected RBCs?
A
Hypoxia and metabolic interference in vital organs
13
Q
Why are only ring forms seen on peripheral blood smear?
A
Because mature forms are sequestered in organs
14
Q
What leads to splenomegaly in recurrent malaria?
A
Splenic processing and filtration of infected RBCs
15
Q
What happens to uninfected RBCs in malaria?
A
Reduced deformability and shortened survival
16
Q
What are the end consequences of RBC destruction?
A
Anemia and jaundice
17
Q
Which Plasmodium species sequester in capillaries?
A
Plasmodium falciparum
18
Q
Which Plasmodium species affect young RBCs?
A
P. vivax and P. ovale
19
Q
Which Plasmodium species affect old RBCs?
A
P. malariae
20
Q
Which Plasmodium species infect all ages of RBCs?
A
P. falciparum
21
Q
Which species can reach very high parasitemia levels?
A
P. falciparum and P. knowlesi
22
Q
What host defense mechanism removes ring-form parasites?
A
Pitting by the spleen
23
Q
What cytokine release is triggered by schizont rupture?
A
Proinflammatory cytokines causing fever
24
Q
Which genetic traits confer malaria protection?
A
Thalassemia
25
How do HbS and HbC reduce severity of malaria?
By impairing parasite growth and reducing PfEMP1 presentation
26
What is premunition in malaria?
Asymptomatic parasitemia with some immunity
27
What factor precludes direct T cell recognition of infected RBCs?
Absence of MHC on infected RBCs
28
What enables strain-specific immunity in malaria?
Antigenic variation on erythrocyte surface
29
What is a classic sign of malaria on physical exam?
Splenomegaly without rash
30
What are the three stages of malaria paroxysm?
Cold stage
31
What is a common symptom of falciparum malaria in children?
Generalized seizures
32
What symptoms help differentiate malaria from dengue?
Splenomegaly (malaria)
33
What organ enlarges due to recurrent malaria?
Spleen
34
What type of anemia is seen in severe falciparum malaria?
Normochromic
35
What is a dangerous consequence of high parasite load?
Cerebral malaria
36
What is the prognosis of cerebral malaria?
~20% mortality in adults
37
What is the best biochemical predictor of death in malaria?
Plasma HCO3 or lactate
38
How does noncardiogenic pulmonary edema occur in malaria?
Unknown cause
39
What are signs of severe malaria-induced renal failure?
Creatinine >265 μmol/L and low urine output
40
What hematologic abnormality differentiates malaria from dengue?
Mild thrombocytopenia in malaria
41
What are signs of hepatic dysfunction in malaria?
Jaundice
42
What are clinical signs of poor prognosis in malaria?
Shock
43
What lab values indicate poor prognosis?
Hypoglycemia
44
What is the typical urine color in hemoglobinuria?
Black
45
What causes metabolic acidosis in malaria?
Anaerobic glycolysis and impaired lactate clearance
46
What causes seizures in cerebral malaria?
CNS inflammation
47
What are the effects of falciparum malaria in early pregnancy?
Fetal loss in early pregnancy.
48
What are the risks of malaria in primi- and secundigravid women in high transmission areas?
Low birth weight and increased infant mortality rates.
49
What are the features of malaria in pregnant women in stable transmission areas?
Asymptomatic mothers despite high parasite burden.
50
How does HIV affect malaria in pregnancy?
Increases risk of higher-density infections
51
What are the features of malaria in pregnant women in unstable transmission areas?
Severe infections with high parasitemia
52
What fetal outcomes are common with severe malaria in unstable areas?
Fetal distress
53
How common is congenital malaria?
Less than 5% of newborns.
54
What factors affect the frequency and severity of congenital malaria?
Timing of maternal infection and parasite density in blood and placenta.
55
How does P. vivax affect birth weight?
Causes low birth weight
56
What is maternal death from hemorrhage at childbirth linked to?
Malaria-induced anemia.
57
Which age group has the most deaths from falciparum malaria?
Young African children.
58
What are common complications of severe malaria in children?
Convulsions
59
How do children respond to antimalarial drugs?
They tolerate them well and respond rapidly.
60
How can malaria be transmitted besides mosquito bite?
Blood transfusion
61
What is the incubation period of transfusion malaria?
Short.
62
What stage is absent in transfusion malaria?
Pre-erythrocytic stage.
63
What is Hyperreactive Malarial Splenomegaly?
A chronic complication with splenic enlargement and immune changes.
64
What are symptoms of hyperreactive malarial splenomegaly?
Abdominal mass
65
What lab findings suggest hypersplenism in malaria?
Anemia and some degree of pancytopenia.
66
Why are patients with hyperreactive malarial splenomegaly prone to infections?
Due to increased vulnerability from immune dysfunction.
67
What should patients with hyperreactive malarial splenomegaly receive?
Antimalarial chemoprophylaxis in endemic areas or treatment in non-endemic areas.
68
What causes Quartan Malarial Nephropathy?
Soluble immune complexes from P. malariae damaging the renal glomeruli.
69
What is the histologic finding in Quartan Malarial Nephropathy?
Focal or segmental glomerulonephritis with basement membrane splitting.
70
Which immunofluorescent pattern has better prognosis in malarial nephropathy?
Coarse-granular IgG3 pattern with selective proteinuria.
71
Is Quartan Malarial Nephropathy common?
No
72
Does Quartan Malarial Nephropathy respond well to treatment?
No
73
What can repeated P. malariae infections lead to?
Nephrotic syndrome.
74
What virus is associated with Burkitt’s lymphoma?
Epstein-Barr virus (EBV).
75
Where is Burkitt’s lymphoma highly prevalent?
In high-malaria-transmission areas of Africa.
76
How does malaria contribute to Burkitt’s lymphoma?
By provoking immune dysregulation and EBV activation.
77
What is the gold standard for malaria diagnosis?
Demonstration of asexual parasites in stained peripheral blood smear.
78
Which stain is preferred for malaria diagnosis?
Giemsa stain at pH 7.2.
79
What is the advantage of acridine orange staining in malaria?
More rapid diagnosis in low parasitemia but cannot speciate.
80
What is the advantage of thick blood smear?
High sensitivity due to parasite concentration (40–100x).
81
What is the advantage of thin blood smear?
Species identification and prognostic information.
82
How is parasitemia density calculated in thin smear?
Number of parasitized RBCs per 1000 RBCs.
83
What is the procedure for a thick smear?
Uneven blood
84
How are parasites counted in a thick smear?
# of parasites/unit volume based on total leukocyte count.
85
What antigen does PfHRP2 test detect?
P. falciparum-specific histidine-rich protein 2.
86
What are the advantages of PfHRP2 tests?
Rapid
87
What are the disadvantages of PfHRP2 tests?
Detects only P. falciparum and remains positive for weeks after infection.
88
What does the Plasmodium LDH test detect?
Genus-specific and P. falciparum-specific bands.
89
What is the limitation of LDH dipstick test?
May miss low-level or non-falciparum species and cannot quantitate.
90
What is the procedure for acridine orange microtube method?
Fluorescence microscopy after centrifugation in specialized tubes.
91
What is the limitation of acridine orange method?
Does not speciate or quantitate parasites.
92
When should malaria treatment be started?
On clinical grounds if lab confirmation is delayed.
93
What level of parasitemia suggests malaria as cause of fever?
>10
94
When is PCR useful in malaria?
For genotyping
95
What are common lab findings in acute malaria?
Monocytosis
96
What are hematologic abnormalities in severe malaria?
Decreased platelets
97
What metabolic changes are seen in severe malaria?
Acidosis
98
What protein abnormality is seen in endemic malaria?
Hypergammaglobulinemia.
99
What are CSF findings in cerebral malaria?
Opening pressure ~160 mmH2O
100
What is the WHO recommended treatment for uncomplicated malaria caused by P. falciparum and P. knowlesi?
Artemisinin-based combination therapy (ACT)
101
What is the treatment for uncomplicated malaria caused by P. vivax, P. malariae, and P. ovale?
Artemisinin-based combination or oral chloroquine (25 mg of base/kg)
102
Which drug is used in ACT for uncomplicated malaria caused by P. falciparum and P. knowlesi?
Artemisinin-based combination therapy (ACT)
103
What should be added to ACT for areas of low transmission to reduce transmissibility of P. falciparum?
Primaquine (0.25 mg/kg)
104
How long is the 3-day ACT regimen typically given for uncomplicated malaria treatment?
3 days
105
Which ACT partner drug regimen is used in uncomplicated malaria treatment?
Artesunate-sulfadoxine-pyrimethamine, Artesunate-amodiaquine, Artemether-lumefantrine, Artesunate-mefloquine, Dihydroartemisinin-piperaquine, Artesunate-pyronadine
106
What should be done if a patient vomits after taking an oral antimalarial drug?
The dose should be repeated after monitoring for 1 hour.
107
What is the dose of primaquine used for eradication of persistent liver stages in P. vivax or P. ovale infection?
Primaquine 0.5 mg of base/kg in East Asia and Oceania, 0.25 mg/kg elsewhere for 14 days
108
What is the radical treatment for P. vivax or P. ovale infection to prevent relapse?
Primaquine 0.5 mg of base/kg in Southeast Asia and Oceania (total dose 7 mg/kg), and 0.25 mg/kg elsewhere (total dose 3.5 mg/kg) for 14 days
109
What should be done if parasitemia level doesn't fall below 25% of the admission value in 72 hours during malaria treatment?
Suspect drug resistance.
110
What are the components of the first-line treatment for uncomplicated falciparum malaria?
Artesunate (4 mg/kg qd for 3 days) plus sulfadoxine (25 mg/kg)/pyrimethamine (1.25 mg/kg)
111
What second-line treatment can be used if artesunate is unavailable for falciparum malaria?
Artemether (3.2 mg/kg IM stat) or quinine dihydrochloride (20 mg of salt/kg IV over 4 hours)
112
What is the role of artesunate in complicated malaria treatment?
Artesunate is the drug of choice for severe falciparum malaria due to reduced mortality rates.
113
What is the dose of artesunate used in complicated malaria treatment?
Artesunate 2.4 mg/kg IV stat, followed by 2.4 mg/kg at 12 and 24 hours, and daily if necessary.
114
Which drug is used for severe malaria when artesunate is unavailable?
Quinine dihydrochloride
115
What is the management for severe malaria-related hypoglycemia?
IV glucose for hypoglycemia (<2.2 mmol/L) and continuous dextrose infusion.
116
What is the first-line treatment for severe malaria-related convulsions?
IV or rectal Benzodiazepines (diazepam, valium)
117
What are the first-line measures for managing acute pulmonary edema in malaria?
Cautious hydration, oxygen, IV diuretics, and intubation if necessary.
118
What is the recommended fluid management strategy in malaria patients with acute renal failure?
Hemofiltration or hemodialysis should be started early.
119
What type of prophylaxis is used to prevent malaria in pregnant women?
Mefloquine is recommended for travel to areas with drug-resistant malaria.
120
How long should travelers take malaria prophylaxis before and after visiting endemic areas?
2 days to 2 weeks before departure, and for 4 weeks after leaving the endemic area.
121
What malaria vaccine is recommended by WHO for use in children in malaria-endemic areas?
RTS,S/AS01 (Mosquirix) is recommended for children living in sub-Saharan Africa and other regions with moderate to high P. falciparum transmission.
